1. Field of the Invention
The invention relates to dispersion technology of carbon nanocapsules, and in particular to a carbon nanocapsule-layered silicate hybrid and a method of preparing the same.
2. Description of the Related Art
As shown in FIG. 1, a carbon nanocapsule (CNC) is a polyhedral carbon cluster composed of an enclosed multilayer graphite structure, whose diameter ranges from 1 to 100 nm but is usually 30-40 nm. As to the graphite layer on the shell of a carbon nanocapsule, the central parts are exclusively six-member rings, the corners are composed of five-member rings, and every carbon atom is sp2 hybrid orbital. The center of the carbon nanocapsule may be hollow or filled with metal as shown in FIG. 2. The carbon nanocapsule is brought about by well-developed graphitic structure, with thermal and electric conductance, high mechanical strength, chemical stability, large superficial content, firm structure and electromagnetic interference shielding. Carbon nanocapsules can be utilized in various fields such as biomedical, energy and optoelectronic application. A serious obstacle to the development of these applications is the poor dispersion behavior of carbon nanocapsules.
Pristine carbon nanocapsules have an aggregation configuration and is not readily processible. FIG. 3 shows the aggregation of carbon nanocapsule under transmission electron microscopy (TEM). Owing to the strong van der Waals force between carbon nanocapsule particles, it is not easy to disperse carbon nanocapsules in solvent, which makes it undesirable for use. To improve the dispersion behavior of carbon nanocapsules, attempts have been made by chemical modification and physisorption. Chemical modification (or chemical functionalization) includes strong oxidation, atom transfer radical polymerization, and free radical polymerization. The mechanism of chemical modification involves surface modification with reactive functionality, followed by grafting with organic long chains. Physical adsorption may be carried out by ultrasonication or grinding with solvent, which involves adsorption of small organic molecules, surfactants, polymers, or proteins only through weak intermolecular interactions such as π-π stacking force and electrostatic force.